The invention relates generally to transducers, and more specifically to transducers with increased thermal conductivity.
Transducers, such as acoustic transducers, have found application in medical imaging wherein an acoustic probe is held against a patient and the probe transmits and receives ultrasound waves, which in turn may facilitate the imaging of the internal tissues of the patient. It may be advantageous to operate the acoustic probe at a maximum permissible acoustic intensity to enable higher quality imaging, which may be achieved via better penetration of the acoustic waves into the patient's tissues. However, operating the acoustic probe at higher acoustic intensities may disadvantageously result in the production of excessive heat in the transducer assembly.
Moreover, there exist limits on the maximum external temperature of an acoustic probe at points of contact with the patient and a technician. Furthermore, in certain modes of operation of the acoustic probe, the heat generated within the transducer elements or within the transducer assembly may cause the temperature of some regions of the probe surface to exceed permissible limits. However, as will be appreciated by one skilled in the art, materials typically employed to fabricate the transducer elements are primarily selected based upon their acoustic properties, and are generally known to possess relatively low thermal conductivity. Furthermore, the transducer elements are generally isolated from one another by dicing kerfs that provide additional thermal insulation of the transducer elements. Hence, the heat generated within the transducer elements is trapped in the acoustic stack causing the face temperature of the probe to rise above the ambient temperature. It may be advantageous to dissipate the heat that may be trapped in the array of transducer elements in order to circumvent the overheating of the patient contact surfaces of the transducer assembly.
Transducer assemblies are generally fabricated employing materials with lower intrinsic thermal conductivity. The low thermal conductivity of transducer assemblies may result in the overheating of the probe. Disadvantageously, many previous attempts to enhance the thermal conductivity of the acoustic probe have had limited effect on the face temperature of the probe and therefore may be ineffective in sufficiently reducing the face temperature enough to prevent discomfort to a patient. Other prior techniques have been more successful at sufficiently reducing face temperature of the probe, but this improvement often comes at the expense of the acoustic performance of the transducer assembly.
It would be desirable draw the heat away from the heat-generating region of the transducer assembly to lower the face temperature of the ultrasound probe to an acceptable level. Further, it would be desirable to lower the face temperature of the probe to facilitate the operation of the probe at a higher transmit power thereby yielding improvements in diagnostic imaging.